1. Field of the Invention
This invention relates generally to the field of electrical connectors and more particularly to an electrical connector system for attaching an ultrasound transducer assembly to an ultrasound system console.
2. Previous Art
An ultrasound imaging system generally includes an ultrasound transducer assembly and a system console. A typical ultrasound imaging system is shown in FIG. 1 and includes electrical connectors for attaching the transducer assembly to the system console. Known ultrasound imaging systems of the type illustrated in FIG. 1 are disclosed in U.S. Pat. Nos. 4,550,607 and 4,669,009, both to Maslak et al. and assigned to the assignee of the present invention. The teachings of these patents are incorporated herein by reference.
The ultrasound transducer assembly generally includes a scan head, an interfacing cable and a connector. The system console includes a mating connector (referred to hereafter as a "system receptacle") for attachment of the transducer assembly, and also includes a display monitor for displaying system generated images.
When properly controlled by the system console, the scan head radiates ultrasound acoustic waves into the body of a patient. The same scan head receives acoustic echoes from internal body organs, and converts these echoes into electrical signals which are then conveyed to the system console through the interfacing cable and the connectors. The electrical signals are then interpreted by the system console and an image of the internal body organ is created and displayed on the monitor.
In an imaging system employing phased array ultrasound, the scan head consists of a multitude of independent piezo-electric elements arranged in a linear array. Such an array and imaging system are disclosed in U.S. Pat. Nos. 4,550,607 and 4,669,009. Typically, each element of the linear array is independently controlled by a separate coaxial signal line within the transducer assembly interfacing cable. Since many coaxial cables are typically involved, the connector interface between the ultrasound transducer assembly and the system console can become quite complex. The important requirements of this interface include:
1. Convenience: The ultrasound practitioner may change the ultrasound transducer assembly several times during the course of a patient examination. Transducers of different frequencies and sizes are required for diverse diagnostic procedures; the optimum transducer for a given patient examination is important in arriving at a correct diagnosis. It is therefore desirable that the operation of the interface connection between the transducer assembly and the console be simple, intuitive, and rugged. PA1 2. Electrical integrity: The quality of the images generated on the display monitor of the system console are very dependent upon the electrical characteristics of the connector interface. Cross talk between the multitude of channels and electrical interference to and from external electrical equipment must be minimized. The frequency of the analog signals passed to and from the transducer assembly can range between 1 MHz and 50 MHz. The signal voltage levels can range from nano-volts to hundreds of volts. Therefore it is desirable that the connector interface be electrically compatible with signals having a broad dynamic range. PA1 3. Longevity: The transducer assembly is attached to the system console thousands of times over the functional life of the assembly. Degradation of the electrical or mechanical interface can affect the quality of the diagnostic results. It is therefore desirable to provide a system having an interface connection which remains sound throughout a long period of use. PA1 a printed wiring board having contact pads on one surface and cable termination pads on an opposed surface, blind vias electrically connecting predetermined contact pads to predetermined cable termination pads through the printed wiring board; and PA1 a housing enclosing the cable termination pads, the housing including an opening for a cable, the opening being adapted for sealing with the cable, PA1 whereby the connector is submersible in a liquid without an intrusion of the liquid onto the cable termination pads, and whereby the connector is submersible in steam at elevated temperature and pressure without intrusive degradation.
Recent concerns over the transmission of communicable diseases have made it desirable to design equipment that is sterilizable. Since the transducer scan head is placed directly on the body during normal examination, or placed within the body during endo-cavity or surgical procedures, it is desirable that the transducer assembly be sterilizable by submersion in liquid solutions containing common disinfectants, or in saturated steam at elevated temperatures. Transducer scan heads that are not submersible can be used in endo-cavity or intra-operative procedures only if encapsulated in a sterile plastic sheath, or the like. This is not only inconvenient, but it degrades the ultrasound image quality because of the more complicated acoustic pathway between the scan head and the body.